OAL Help!

aggie_2010 · February 20, 2011, 10:46 PM

I'm reloading .270 Win. using RCBS dies, Lee #2 shell holder, and an RCBS Rock Chucker Supreme press. All of the brass is virgin Winchester brass.

Here's what I've done so far.
1) Resized all of the brass using the FL RCBS Die.
2) Trimmed all of the brass to 2.530"
3) Chamfered and deburred the brass
4) Loaded min. amount of powder according to my manual.
5) Seated bullet (.277" 140gr Hornady BTSP) without crimping

I used a dummy round (same brass, also resized, trimmed, chamfered and deburred as well) to set bullet overall depth to 3.335". Now, every round that is cranked out is + or - .010". What the heck am I doing wrong? I've setup the seating stem using several dummy rounds only to have the same problems after all of this.

Hog Buster · February 20, 2011, 11:32 PM

Measure the length of the bullets. With soft points there’s sometimes a bit of difference in their length. They may be all seated to the same depth, but because of varying bullet length your COL will fluctuate. Remember they're being seated via the ogive, not the tip.

Also make sure there’s no slack in your press

farmerboy · February 20, 2011, 11:56 PM

Thats exactly right, the die is seating them with the bullets ogive, olgive (however you spell it) anyways some bullet brands are more consistant than oters and some less but they will be fine. By the way what bullet brand and type are you reloading?

aggie_2010 · February 21, 2011, 12:20 AM

I measured several of the bullets and found that they differed up to about .005" at most. Hopefully that is what is causing my headaches with OAL.

Slack in the press... What exactly do you mean, and what are ways to fix it?.. Make sure the nuts/bolts on the arm linkage are tight?

Bullets are .277 140gr Hornady BTSP

Also, what is the best way to measure the OAL? Buy an ogive measuring tool, and see what OALs fit my rifles throat best? What tool do you use?

Hog Buster · February 21, 2011, 12:42 AM

Slack in the press; Make sure that everything is tight. Dies in press, seating stems in dies, no thrash in seating stem, press pivot pin is not worn and that you are making full strokes when reloading, yeah make sure nuts and bolts are tight, especially the one operating the handle......

etc.

However, it seems that your problem is bullet length. Best tool for all measuring is a dial caliper. I presume that you’re new to reloading. If so just stick to the published COL for now. After a bit more experience you can start playing. Don’t get caught up in nonessential details at first.

The ogive of the bullet is it’s round tapered front end. Different bullets have different ogives. If you change bullets more than likely you’ll have to readjust your seating stem.

While COL is somewhat important a few thousandths isn’t much to worry about . If it concerns you that much buy bullets with a cannalure groove, end of problem.

As an Addendum: On some bullets of the same brand and style the ogive differs slightly this can also cause the COL to vary, but not enough to worry much about..

One more thing. Hornady SST's have better consistancy and shoot better in my 270 than others.

wncchester · February 22, 2011, 07:17 PM

"every round that is cranked out is + or - .010"."

A spread of 20 thou is a lot of variation. As you've learned, much of it is in the bullets themselves. Most of the rest comes from inconsistant operation of the press during seating; use the same stoke, pressure and timing. There is no way to "adjust" the press linkage because it's not needed.

No rifle cares a bit where a bullet tip hangs in space. All that matters is the jump to the rifling and that isn't nearly as critical as some presume, there is a seating range, usually 10-15 thou wide, in which the seating is as good as it needs to be.

February 20, 2011, 10:46 PM	#1
aggie_2010 Member Join Date: January 19, 2011 Location: College Station, Texas Posts: 24	OAL Help! I'm reloading .270 Win. using RCBS dies, Lee #2 shell holder, and an RCBS Rock Chucker Supreme press. All of the brass is virgin Winchester brass. Here's what I've done so far. 1) Resized all of the brass using the FL RCBS Die. 2) Trimmed all of the brass to 2.530" 3) Chamfered and deburred the brass 4) Loaded min. amount of powder according to my manual. 5) Seated bullet (.277" 140gr Hornady BTSP) without crimping I used a dummy round (same brass, also resized, trimmed, chamfered and deburred as well) to set bullet overall depth to 3.335". Now, every round that is cranked out is + or - .010". What the heck am I doing wrong? I've setup the seating stem using several dummy rounds only to have the same problems after all of this.

February 21, 2011, 12:42 AM	#5
Hog Buster Senior Member Join Date: October 26, 2009 Location: Pointe Coupee, Louisana Posts: 772	Slack in the press; Make sure that everything is tight. Dies in press, seating stems in dies, no thrash in seating stem, press pivot pin is not worn and that you are making full strokes when reloading, yeah make sure nuts and bolts are tight, especially the one operating the handle...... etc. However, it seems that your problem is bullet length. Best tool for all measuring is a dial caliper. I presume that you’re new to reloading. If so just stick to the published COL for now. After a bit more experience you can start playing. Don’t get caught up in nonessential details at first. The ogive of the bullet is it’s round tapered front end. Different bullets have different ogives. If you change bullets more than likely you’ll have to readjust your seating stem. While COL is somewhat important a few thousandths isn’t much to worry about . If it concerns you that much buy bullets with a cannalure groove, end of problem. As an Addendum: On some bullets of the same brand and style the ogive differs slightly this can also cause the COL to vary, but not enough to worry much about.. One more thing. Hornady SST's have better consistancy and shoot better in my 270 than others. __________________ Those who beat their guns into plows, will plow for those who don't.-Thomas Jefferson Last edited by Hog Buster; February 21, 2011 at 12:51 AM. Reason: CRS

February 20, 2011, 11:32 PM	#2
Hog Buster Senior Member Join Date: October 26, 2009 Location: Pointe Coupee, Louisana Posts: 772	Measure the length of the bullets. With soft points there’s sometimes a bit of difference in their length. They may be all seated to the same depth, but because of varying bullet length your COL will fluctuate. Remember they're being seated via the ogive, not the tip. Also make sure there’s no slack in your press __________________ Those who beat their guns into plows, will plow for those who don't.-Thomas Jefferson

February 20, 2011, 11:56 PM	#3
farmerboy Junior member Join Date: May 16, 2009 Location: Central Texas Posts: 1,343	Thats exactly right, the die is seating them with the bullets ogive, olgive (however you spell it) anyways some bullet brands are more consistant than oters and some less but they will be fine. By the way what bullet brand and type are you reloading?

February 21, 2011, 12:20 AM	#4
aggie_2010 Member Join Date: January 19, 2011 Location: College Station, Texas Posts: 24	I measured several of the bullets and found that they differed up to about .005" at most. Hopefully that is what is causing my headaches with OAL. Slack in the press... What exactly do you mean, and what are ways to fix it?.. Make sure the nuts/bolts on the arm linkage are tight? Bullets are .277 140gr Hornady BTSP Also, what is the best way to measure the OAL? Buy an ogive measuring tool, and see what OALs fit my rifles throat best? What tool do you use?

February 22, 2011, 07:17 PM	#6
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	"every round that is cranked out is + or - .010"." A spread of 20 thou is a lot of variation. As you've learned, much of it is in the bullets themselves. Most of the rest comes from inconsistant operation of the press during seating; use the same stoke, pressure and timing. There is no way to "adjust" the press linkage because it's not needed. No rifle cares a bit where a bullet tip hangs in space. All that matters is the jump to the rifling and that isn't nearly as critical as some presume, there is a seating range, usually 10-15 thou wide, in which the seating is as good as it needs to be.